Select EMP with max SAL from each DEPT - sql

Question

I´m having a bad time with a SQL query. I´m using oracle default tables:
'EMP' TABLE
http://imageshack.us/photo/my-images/850/sinttuloxps.png/
AND
'DEPT' TABLE
http://imageshack.us/photo/my-images/19/assayp.png/
I wan´t to get the employee with the highest salary in each department.
I´m using SQLPLUS.
Thanks in advance!
ALSO CODE:
CREATE TABLE dept (
deptno numeric(2,0) NOT NULL,
dname character varying(14),
loc character varying(13),
CONSTRAINT dept_pkey PRIMARY KEY (deptno)
);
CREATE TABLE emp (
empno numeric(4,0) NOT NULL,
ename character varying(10),
job character varying(9),
mgr numeric(4,0),
hiredate date,
sal numeric(7,2),
comm numeric(7,2),
deptno numeric(2,0),
CONSTRAINT emp_pkey PRIMARY KEY (empno),
CONSTRAINT emp_deptno_fkey FOREIGN KEY (deptno) REFERENCES dept(deptno),
CONSTRAINT emp_mgr_fkey FOREIGN KEY (mgr) REFERENCES emp(empno)
);
INSERT INTO dept (deptno, dname, loc) VALUES (10, 'ACCOUNTING', 'NEW YORK');
INSERT INTO dept (deptno, dname, loc) VALUES (20, 'RESEARCH', 'DALLAS');
INSERT INTO dept (deptno, dname, loc) VALUES (30, 'SALES', 'CHICAGO');
INSERT INTO dept (deptno, dname, loc) VALUES (40, 'OPERATIONS', 'BOSTON');
insert into emp values (7839, 'KING' , 'PRESIDENT', NULL, to_date('17/11/81','dd/mm/yy') , 5000, NULL, 10);
insert into emp values (7566, 'JONES' , 'MANAGER' , 7839, to_date('02/04/81','dd/mm/yy') , 2975, NULL, 20);
insert into emp values (7902, 'FORD' , 'ANALYST' , 7566, to_date('03/12/81','dd/mm/yy') , 3000, NULL, 20);
insert into emp values (7369, 'SMITH' , 'CLERK' , 7902, to_date('17/12/80','dd/mm/yy') , 800, NULL, 20);
insert into emp values (7698, 'BLAKE' , 'MANAGER' , 7839, to_date('01/05/81','dd/mm/yy') , 2850, NULL, 30);
insert into emp values (7499, 'ALLEN' , 'SALESMAN' , 7698, to_date('20/02/81','dd/mm/yy') , 1600, 300, 30);
insert into emp values (7521, 'WARD' , 'SALESMAN' , 7698, to_date('22/02/81','dd/mm/yy') , 1250, 500, 30);
insert into emp values (7654, 'MARTIN' , 'SALESMAN' , 7698, to_date('28/09/81','dd/mm/yy') , 1250, 1400, 30);
insert into emp values (7782, 'CLARK' , 'MANAGER' , 7839, to_date('09/06/81','dd/mm/yy') , 2450, NULL, 10);
insert into emp values (7788, 'SCOTT' , 'ANALYST' , 7566, to_date('09/12/82','dd/mm/yy') , 3000, NULL, 20);
insert into emp values (7844, 'TURNER' , 'SALESMAN' , 7698, to_date('08/09/81','dd/mm/yy') , 1500, 0, 30);
insert into emp values (7876, 'ADAMS' , 'CLERK' , 7788, to_date('12/01/83','dd/mm/yy') , 1100, NULL, 20);
insert into emp values (7900, 'JAMES' , 'CLERK' , 7698, to_date('03/12/81','dd/mm/yy') , 950, NULL, 30);
insert into emp values (7934, 'MILLER' , 'CLERK' , 7782, to_date('23/01/82','dd/mm/yy') , 1300, NULL, 10);

Answer 1

You can also use the analytical RANK() function:
SELECT * FROM (
SELECT
Dept.DeptNo,
Dept.DName,
Emp.EName,
Emp.Sal,
RANK() OVER (PARTITION BY Dept.DeptNo ORDER BY Emp.Sal DESC) AS DeptSalRank
FROM Emp
INNER JOIN Dept ON Emp.DeptNo = Dept.DeptNo
)
WHERE DeptSalRank = 1

Answer 2

Classic greatest-n-per-group query. Here is what you want:
select dept.dname, emp.empno, emp.ename, emp.sal
from emp
inner join dept on emp.deptno = dept.deptno
inner join
(
select emp.deptno, max(emp.sal) sal
from emp
group by emp.deptno
) ss on emp.deptno = ss.deptno and emp.sal = ss.sal
order by emp.sal desc
Here is a working fiddle: http://sqlfiddle.com/#!4/7147b/6
Additionally, you might want to checkout a different approach. Look here (SQL Select only rows with Max Value on a Column) to see an interesting answer on the topic.

Answer 3

The following query will omit duplicate values
SELECT DEPTNO, MAX(SAL) FROM EMP GROUP BY DEPTNO;
The following query will include the duplicate values
SELECT * FROM EMP WHERE (DEPTNO,SAL) IN
( SELECT DEPTNO, MAX(SAL) FROM EMP GROUP BY DEPTNO)

Answer 4

As short as the question: SELECT DeptID, MAX(Salary) FROM Employees GROUP BY DeptID

Answer 5

Tested. Here is the query:
Select outemp.Employee_ID, outemp.First_Name, outemp.Last_Name
From Hr.Employees outemp,
HR.Departments outdept,
(Select Max(e.salary) maxsal, D.Department_ID Dept_ID From HR.EMPLOYEES e, HR.Departments d
WHERE e.Department_ID = d.Department_ID
Group By d.Department_ID) DummyTable
where outemp.Department_ID = outdept.Department_ID
AND outdept.Department_ID = DummyTable.Dept_ID
AND outemp.Salary = DummyTable.Maxsal

Answer 6

list of top 10 highest paid employee detail
(SELECT *, RANK() OVER (ORDER BY Emp.Sal DESC)AS DeptSalRank
FROM Emp INNER JOIN Dept ON Emp.DeptNo = Dept.DeptNo) LIMIT 10;